How to remap key with shift and alt modifier using xmodmap?

Just found out, heuristically ! Look at the following :

xmodmap -e "keycode 38 = a A aacute Aacute ae AE ae"

It's basically

  1. a: normal a
  2. A: shift + a
  3. á: altgr + a
  4. Á: shift + altgr + a
  5. æ: [some modifier combination] + a
  6. Æ: shift + [some modifier combination] + a
  7. æ: ???

So just reconfigure the key with the representations you want. For example, I reassigned period + altgr to interpunct (a bit expedient though):

xmodmap -e "keycode 60 = period greater 0x00b7 0x00b7 0x00b7 0x00b7"